Thermostat



Patented Dec. 2, 1941 UNITED STATES, PATENT OFFICE THERMOSTAT EdwardBletz, Lexington, Ohio, assignor to Westinghouse Electric &Manufacturing Company, East Pittsburgh, Pa. a corporation oiPennsylvania Application April 29, 1939, Serial No. 270,813

7 Claims.

My invention relates to heat-responsive devices, and more particularlyto bimetallic thermostats. I

An object of my invention is to provide a thermostat having a bimetallicmember, portions of which move, upon increasing temperatures, firsttoward. cooperating contacts and then at selectively predeterminedtemperature values in an opposite direction away from the contacts fordisating contacts by flexing towards the contacts,

pointed out specifically in the course of the following description of adevice embodying my invention, or will be apparent from suchdescription.

In the accompanying drawing,

Figure 1 is a top plan view of a device embodyin my invention;

Figs. 2, 3 and 4 are sectional views taken along the line 11-11 of Fig.1, illustrating the device in various operating positions;

. Fig. 5 is a top plan view of ajmodifled form of thedevice shown inFig. 1;

I Figs. 6, 7 and 8 are sectional views taken along the line V'I-VI ofFig. 5, illustrating the device in its various operating positions;

Fig. 9 is a top plan view of an additional modiflcation of the deviceshown in Fig. 1; and

Figs. 10, 11 and 12 illustrate the device of Fig. 9 in its variousoperating positions.

' Referringin particular to Figs. 1 to -i,'inclusive,-

of the accompany drawing, I show a thermostatic device lll, including abase or supporting structure I2, a bimetallic member ll, cooperatingcontacts It and an adjusting device I. suppoJed by the structure l2 andoperatively associated with the bimetallic member ll for controlling theoperation thereof.

The base I! is formed, in this instance, of an elongated metallic stripinto substantially an inverted U-shaped member having outwardlyextending supporting flanges 20 and 22 adapted to rigidl attach the baseor structure I! to any desired device. It is to be understood that,while the base i2 is illustrated as being formed of a metalliccomposition, such base or supporting structure may be formed from anysuitable phenolic resin or the like.

The bimetallic member I4 is, in this instance, an elongated strip-typethermostatic member with an aperture 24 located intermediate the endsthereof for a purpose hereinafter described. The bimetallic member 14 isrigidly attached to the base or supporting structure I2 by means of asuitable block or spacer 26 and a screw 28. This method of fastening thestrip-type bimetallic member l4 to the supporting structure l2 permitssuch bimetallic member to flex about the spacer'25 of base I! as afulcrum.

The relatively high expansive material of the bimetallic member I4 is,in this instance, located on the lower side thereof. The application ofheat thus causes the free end of the bimetallic member H to rotativelyflex upwardly or away from the high expansive side in a well-knownmanner. However, when the movement of the free end is stopped and bothends of-the bimetallie member [4 are restrained'from upward movement,the central portion of the bimetallic memher will reverse its travel andbow downwardly or toward the high expansive side,'as hereinafter morefully set forth. This, in turn, actuates the cooperating contactsw IS inthe manner as hereinafter described.

The cooperating contacts Ii include a stationary contact 30 and amovable contact 32 which are respectively associated with suitableterminals 34 and 3B. 'The contact 30 is, in this instance, rigidlyattached to the lower surface of the central portion of the base orsupporting structure I! by means of the terminal 34. The terminal M hasa rivet portion 31 located on the lower portion thereof. This rivetportion 11 exably insulate the terminal 3! and contact 30 from a thesupporting structure It.

The movable contact 32 is flexibly or loosely attached to the supportingstructure [2 by means of the second terminal 36 and flexible mountingmember 44. The'terminal 36 has a downwardly extending rivet portion 40functionally .integral therewith. The rivet portion 40 is adapted toextend through the supporting structure I2, a suitable spacing member 42and the flexible mounting member 44. The rivet portion 40 thus isadapted to rigidly attach the terminal 36, spacer member 42, andflexible mounting member 44 to the supporting structure l2. Suitableinsulating members 39 may likewise be positioned intermediate theterminal 36 and spacer member 42 to insulate such members from thesupporting structure I2. The flexible mounting member 44 may be of anysuitable resilient current carrying material, such as stainless steel.The resilient supporting member 44 extends substantially par aliel tothe bimetallic member I4 intermediate such member and the supportingstructure I2, and has rigidly attached at the free end thereof themovable contactor 32.

A suitable pin 46 is insulatedly attached to the flexible mountingmember 44 intermediate the ends thereof. The pin 46 is rigidly attachedat its upper end to the flexible member 44, and is inserted through theaperture 24 in the bimetallic member I4. An enlarged head portion 48 islocated at the lower end of the pin 46 to prevent the free passage ofsuch pin through the aperture 24. The aperture 24 is of such size andshape with respect to the pin 46 that there may be a relatively freemovement therebetween. However, the head 48 of pin 46 will prevent thepin from passing through the bimetallic member I4. Therefore, it followsthat the bimetallic member I4 may move upwardly with respect to theflexible mounting member 44 and movable contact 32 without causing anymovement of the pin 46, flexible member 44 or contact 32 (see Fig. 2),and that, as the bimetallic member I4 bows downwardly, the engagement orcooperation of head 48 and bimetallic member I4 will cause the pin 46,resilient member 44 and movable contact 32 to be moved downwardlytherewith.

It, therefore, follows that the central portion of the bimetallic memberl4 may move toward the cooperating contacts I6 without causing anycorresponding movement of the pin 46 and movable contact 32, but uponmoving away from the cooperating contacts, such member will, through thecooperation of pin 46, cause the movable contact 32 to move therewith soas to disengage structure I2 by being rotated within the sleeve 56. Theadjusting device I8 is positioned upon the supporting structure l2 insuch a location that the lower ball-headed end 52 of the adjusting screw56 will cooperate with the free end or movable end of the bimetallicmember I4. The relative positions of the adjusting screw 56 thusdetermine the position of the free end of the bimetallic member I4 asthe central portion thereof changes its direction from a rotativeflexing action to a bowing action, as hereinabove described. It is to beunderstood that the adjusting screw 50 may thus be selectivelypositioned to any desired location so as to selectively determine theoperating characteristics of the bimetallic member I4.

When operating the thermostatic device IIl embodying my invention, theterminals 34 and 36 are operatively associated with a circuit which itis desired to have controlled by means of such device. Assuming that thebimetallic member I4 is in a relatively cold condition, the cooperativecontacts l6 will be engaged (see Fig.2). The bimetallic member I4willthus be substantially horizontal parallel to the base I2. bimetallicmember I4 increases in temperature,

such member will rotatively flex u wardly about the spacer 26 as afulcrum. The p" 46 and movable contact 32 will, however, remainsubstantiallystationary while the bimetallic member I4 moves upwardly.

The free end of the bimetallic member I4 will continue its upward traveluntil it strikes the ball-headed end 52 of the adjusting screw 50.Thebimetallic member I4 will thus, upon the continued increase intemperature, bow downwardly, whereupon the central portion thereofpredetermined selected distance away from the high expansive side of thebimetallic member and then bows in a reverse direction towards the highexpansive side so as to actuate or disengage the cooperating contactsI6.

If it be desired to manually disengage the cooperating contacts I6, theadjusting screw 50 may-be run down within the sleeve 56 so as to forcethe free end of the bimetallic member I4 downwardly or in a clockwisedirection. This, in turn, through the cooperative action of pin 46 andflexible mounting member 44 causes the movable contact 32 to beseparated from the stationary contact 30, disengaging the cooperatingcontacts I6 in a well-known manner. To reengage the cooperating contactsI6, it is thus necessary to manually rotate the adjusting screw 50 sothat the free end of the bimetallic member I4 will be returned to itsnormal position, as hereinabove described.

Referring to Figs. 5 to 8, inclusive, I show a modified form ofthermostat embodying my invention comprising a supporting structure l2,bimetallic member I4, cooperating contact I6 and adjusting device I8.The supporting structure I2 is similar to that illustrated in Figs. 1 to4, inclusive, and as hereinabove described. Likewise, the bimetallicmemberfl' is substantially the same as hereinabove described, beingrigidly attached to the supporting structure I2 by means of a spacerblock 26 and screw 28. The adjusting device I8 is positioned upon thesupporting structure I2 to selectively adjust the operatingcharacteristics of the bimetallic mem-,

ber I4 in a manner as hereinabove described. The cooperating contact I6comprises, in this instance, a movable contact 51 and a stationarycontact 58. The movable contact-51 is rigidly Then as the 3 ment of suchmember.

attached to and insulated from the bimetallic member I4 intermediate theends thereof. The .movable contact 58 includes a depending shaft orrivet portion 80 which is adapted to extend through the bimetallicmember I4. The lower end of the rivet portion 80 is riveted over upon asuitable washer 82 to rigidly attach the movable contact 51 to thecentral portion of the bimetallic member.

A suitable flexible member 84 is attached to the 1' movable contact 51and bimetallic member I4 at one end and to a terminal 88 at the otherend. The flexible member 84 is located beneath the movable contact 51,and is, therefore, rigidly attached therewith to the bimetallic memberI4, 1'.

therefrom by means of suitable insulating members I0. The contact 58includes an upwardly extending rivet portion I2 which extends throughthe supporting structure I2 and a second terminal I4, whereupon theupper end thereof is riveted over against the terminal 14 to rigidlyattach such contact and terminal to the supporting structure.

The bimetallic member I4 is physically similar to member I4 and ismounted upon the supporting structure in a manner similar to thathereinabove described. Such member will, therefore, when at a normaloperating temperature, remain substantially horizontal. The cooperatingcontacts I8 are thus engaged (see Fig. 6), and the free end of thebimetallic member I4 is located somewhat below the ball-head 52 of theadjusting device I8.

With an increase in temperature of the bimetallic member I4', suchmember will tend to deflect upwardly. However, this action increases thecontact pressure between the movable contact 51 and the stationarycontact 58. With the increased temperature of the bimetallic member I4,the free end of such member will flex upwardly and engage the ball-head52 of adjusting device I8, restraining any further upward move- Thecentral portion of such member will then. upon a continued increase intemperature, change its direction of rotation and bow downwardly. Themovable contact 5'I rigidly attached thereto will correspondingly movedownwardly. The cooperating contacts I6 will thus be disengaged. (seeFig. 7).

The adjusting device I8 may likewise manually disengage and reengage thecooperating contacts I8 as hereinabove described (see Fig. 8).

Still a further modification of the device embodying my invention isillustrated in Figs. 9 to 12, inclusive, in which I show a thermostaticdevice 88 comprising a supporting structure 82, a bimetallic member 84,cooperating contacts 88 and an adjusting device 88. The supportingstructure 82 is substantially the same as the supporting structure I2,as hereinabove described. However, the structure 82 has a verticallyextending cylindrical aperture 90 located at substantially the midpointthereof to permit'an infor a purpose hereinafter described. Thebimetallic member 84 is substantially the same as th bimetallic memberI4 hereinabove described. However, the high expansive portion of thebimetallic member 84 is located on the upper surface thereof. The freeend of the bimetallic member 84 will thus move downwardly with anincreasing temperature. The bimetallic member 84 is rigidly attached atone end to the supporting structure 82 by means of a spacer block 94 andscrew 98 substantially as hereinabove described.

The cooperating contacts 88, in this instance, are located above the topsurface of the supporting structure 82 and include a stationary contact98 and a movable contact I00. The stationary contact 98 is rigidlyattached to the terminal I02 by means of a rivet portion I04 thereof.The contact 98 and terminal I02 are insulated from the supportingstructure 82 by means of suitable insulating washers I08. The movablecontact I00 is rigidly attached to the free end of a flexible currentcarrying member I08. The rigid or stationary end of the flexible currentcarrying member I08 is located beneath a second terminal I I0 which isrigidly attached to supporting structure 82 by means of a lower integralrivet portion H2. The flexible member I08 and terminal III! areinsulated from the supporting structure 82 by means of suitableinsulating members I I4. The flexible member I08 is located above theinsulating pin 92, in such a manner that the pin 92 when biased upwardlywill force the resilient member I08 and movable contact I00 upwardly,this action, in turn, causing the cooperating contacts '88 to bedisengaged, as hereinafter described.

The pin 92 slidably mounted within the supporting structure 82cooperates with the flexible member I08 atone end thereof and anintermediate point of the bimetallic member 84 at the other endthere0f.- Thus the bimetallic member 84 may, under suitable conditions,force the pin 92 upwardly so as to disengage or actuate the cooperatingcontacts 88.

The adjusting device 88 includes a threaded screw member II8 threadedlymounted within a sleeve H8. The screw H8 has a flange I20 located at thelower end thereof. The flange I20 is adapted to engage the free end ofbimetallic member 84 as the adjusting screw II 6 is run upwardly. Theflange I20 is thus adapted to bodily move the free end of the bimetallicmember 84 upwardly or selectively predetermine its operating limits. v

' When operating the thermostatic device 80 with the bimetallic member84 at a normal temperature, such member will .be substantiallyhorizontal, (see Fig-1i). The cooperating contacts 88 will thusbeengaged. Then as the bi-metallic member 84 increases in temperature,such member will rotatively flex downwardly about the spacer block 94and screw 98 until the free sulating pin 92 to be slidably mountedtherein end thereof engages the flange I20 of the adjusting device 88.The central portion of the bimetallic member 84 will then change itsdirection of movement and .start to bow upwardly. This upward movementwill thus cause the insulating pin 92 to likewise move upwardly With acontinued upward movement thereof, the pin 92 will first engage theflexible member I08 and then cause such flexible mounting member I08 andmovable contact I00 to be moved upwardly, disengaging the cooperatingcontacts 88 The bimetallic member 84 will then, upon coolingsufficiently, return to its original position with a reversal in thedirection of movement of the central, portion thereof and permitting thereengagement of the cooperating contacts 98 and I00 If it be desired tomanually operate the thermostatic device 80, the adjusting screw H6 ismoved upwardly in a vertical direction, whereupon the flange IROthereofwill force the free end of the bimetallic member 84 upwardly The pin 92will then be moved vertically so as to disengage the contact Hlll in amanner hereinabove described. Then when it is desired to reengage thecooperating contacts 86, the adjusting screw is run down to its normaloperating position in a well known manner.

It is, therefore, obvious that I have provided thermostatic deviceswhich include a bimetallic member capable of rotatively flexing for apredetermined selective distance and then moving in an oppositedirection to actuate the cooperating contacts.

Various other modifications may be made in the device embodying myinvention without departing from the spirlt'and scope thereof, and Idesire, therefore, that only such limitations shall be placed thereon asare imposed by the prior art and the appended claims.

I claim as my invention:

1. A thermostatic device comprising, in combination, cooperatingcontacts including a movable contact, a bimetallic member for actuatingthe movable contact, an adjusting device for selectively adjusting theoperations of the member,

and a flat spring attached to the movable contact and having alost-motion connection with the bimetallic member for permitting freemovement of the member below the selected contactactuating value thereofand for bodily moving the movable contact above such actuating value.

2. A thermostatic device comprising, in combination, a terminal,cooperating contacts including a movable contact, a bimetallic memberfor actuating the movable contact, said movable contact beinginsulatedly attached to an intermediate point of the bimetallic memberand resiliently attached to the terminal, an adjusting device forselectively adjusting the operation of the bime tallic member, saidmember adapted to increasingly bias the movable contact against thestationary contact until such member engages the adjusting devicewhereupon the member will change its curvature and separate thecontacts.

3. A thermostatic device comprising, in combination, cooperatingcontacts including a movable contact, a resilient member carrying saidmovable contact, a bimetallic member for actuating the movable contactand resilient member, an adjusting device adapted to cooperate with themoving end of such bimetallic member for selectively adjusting theoperations of such member, said member adapted to rotatively flextowards the adjusting device and upon engaging the device to bow in anopposite direction between its rigid support and the device foractuating the movable contact and resilient member.

4. A thermostatic device comprising, in combination, a supportingstructure, cooperating contacts including a movable contact, abimetallic member for actuating the movable contact, and" an insulatingpin cooperating with the bimetallic member for transmitting theactuating movementsbf the member to the movable contact, said bimetallicmember upon an increase in temperature adapted to flex away from themovable contact for a predetermined selective distance and then to bowtowards the movable contact for actuation of such contact.

5. A thermostatic device including, in combination, cooperatingcontacts, a mechanical stop member, a thermal responsive device, andmeans other than said thermal responsive device for biasing saidcontacts to a certain position. said thermal responsive device under theinfluence of heat substantially continuously moving first in onedirection until it engages said stop member and then in an oppositedirection for thereafter effecting a single actuation of said means anda contact to a different position.

6. A thermostatic device including, in combination, normally closedcontacts, a stop member,

a bimetallic member, and separate resilient means for biasing saidcontacts to said closed position, said bimetallic member under theinfluence of heat changing its direction of curvature upon engaging saidstop member while moving substantially continuously for thereaftereflecting a single actuation of said means and a contact to a differentposition.

7. A thermostatic device including, in combination, cooperatingcontacts, an adjustable stop

